This position would all but rule him out of any coalition that included New Zealand First.
NZ First leader Winston Peters said last month his party wants a public referendum in the next parliamentary term on whether to keep or get rid of the seats. It is a bottom line for his party.
Morgan told an audience celebrating the Maori King's coronation anniversary that the retention of the electorates was non-negotiable.
"We will not support a government which would put the current Maori seats at risk through referendum or any other means."
National also has a formal policy of abolishing the Maori seats, though Prime Minister Bill English has said the party is not pursuing it. His predecessor Sir John Key once warned that there would be "hikois from hell" if National tried to scrap the 150-year-old Maori electorates.
They were created in 1867 to improve Maori representation in Parliament and have survived numerous attempts at abolition. Initially four seats, they expanded to seven seats in 2002.
A One News Colmar Brunton poll released last month showed 55 per cent of New Zealanders wanted the seats to stay and 36 per cent wanted them scrapped immediately or in future.
In his speech, Morgan also returned to one of his most common targets, Winston Peters, who he has previously described as an "nothing more than an Uncle Tom" because of his anti-Treaty views.
"We see that man as a turncoat, a person who has sold Maori the Treaty down the river in his quest for regressive, conservative votes from the far right," he said today.
Peters' views on Maori were as "disgusting" as former National leader and Hobson's Pledge co-founder Don Brash, he said.
While Top is not running in the Maori electorates, Morgan said he still wanted Maori to cast their party votes for his party. Top offered more than mainstream parties because it recognised that "partnership and co-operation will be vital to improve many facets of life in the country", he said.
Top is polling at about 2 per cent, and needs 5 per cent to get into Parliament.