Powell was likely to hear Pakistan concerns about the impact of a long military campaign in Afghanistan, the fallout from civilian casualties, a future post-Taleban administration and the 54-year dispute with nuclear arch-rival India over Kashmir.
Pakistan insists any future administration in Afghanistan be broad-based and representative, and that Taleban foes in the Northern Alliance not be allowed complete control.
Powell said: "What we're doing really is contingency planning and getting ready for the possibility that some time in the near future there could be a need to respond to the collapse of the government, if one can call that evil regime a government."
He said he had appointed Richard Haass as his special representative on Afghanistan.
He would talk to the United Nations this week on the makeup of a future Afghan government.
Powell, who will also visit India during the three-nation Asian trip, told reporters on the flight from Washington that he would listen to the concerns of both Islamabad and New Delhi.
"This gives me a chance to listen to them, to hear their assessment, hear their concerns and see how we can be helpful," he said.
"I'm sure both countries will have the chance to talk about the future of Afghanistan."
Powell will also attend the Asia Pacific Economic Cooperation forum in China this weekend.
The visit could also present a new chance for Pakistan in a relationship that had faltered since its 1998 nuclear tests and a coup the following year led by Musharraf.
A senior State Department official said Washington was examining Pakistan's performance across the board with a view to further easing sanctions, but deliveries of military equipment were not on the table and had not been requested.
The US lifted an array of military, economic and other sanctions against Pakistan after it agreed to support military strikes against Afghanistan's Taleban, and their "guest", Saudi-born dissident Osama bin Laden, prime suspect in last month's attacks.
Pakistan has given the US access to its air space and intelligence and offered logistical support that includes use of airports at Jacobabad and Pasni, on the Arabian Sea, triggering anger from radical Islamic parties.
Pakistan says the US will not launch combat operations from bases in Pakistan, but in Jacobabad there have been violent protests against the US presence, in which at least one Taleban supporter was killed.
Pakistan said earlier that all aspects of the Afghan situation, including the duration of the military operation, as well as the Kashmir issue, would be taken up with Powell.
Powell praised Musharraf for his "bold and courageous" support and his decision within 24 hours to throw his weight behind using force to hunt down bin Laden.
But Powell's arrival fell under a shadow after Indian forces launched heavy mortar fire on Pakistani positions across the Line of Control dividing the foes in the Himalayan region of Kashmir.
Pakistan returned fire and said one person was killed and 25 wounded in the attacks.
India rules about 45 per cent of Kashmir and Pakistan a third.
The two countries have fought two of their three wars since independence from Britain in 1947 over Kashmir. China holds the rest of the territory.
Monday's action in Kashmir followed a terrorist bombing there October 1 that killed about 40 people.
It left US officials worried that India and Pakistan would turn their attention on each other instead of cooperating in the global counter-terrorism effort.
National security adviser Condoleezza Rice said that she, President George W. Bush and Powell had called many top Indian and Pakistani officials to emphasize the importance of "not having a flare-up" over Kashmir.
- REUTERS
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