In December, he told the House he was expecting that number to be 16,000.
"Our modelling has always been based on the idea that in the first three years, we'll probably deliver about 16,000 homes," he said at the time.
Those numbers were based on forecasts that the Government would oversee the building of 1,000 houses this year, 5,000 the next, and 10,000 in 2021.
Those targets have since been scrapped.
"We share everyone's disappointment with the disappointing number that KiwiBuild has achieved in the first year and a half of the programme," he said during question time today.
"We wished that those numbers were better – that's why we're doing the reset."
National housing spokeswoman Judith Collins said the KiwiBuild policy was "a dog" and Twyford's admission today was evidence of that.
Speaking to media outside the House, Twyford said the 1500 expected homes were only the KiwiBuild homes that were currently contracted and committed right now.
"We're working as hard as we can, so I would expect over time we will push that number up significantly."
He would not, however, be drawn on how much "significantly" accounted for.
"We always expected that the buying off the plans scheme would be how we started to get some initial KiwiBuild homes built in the first year or two."
This morning, before going into Labour's weekly caucus meeting, Twyford was quizzed about how many KiwiBuild homes would be completed by July 1.
He said there were 83 KiwiBuild homes that had been completed, with 400 under construction.
But asked if there would be 300 KiwiBuild homes by July 1, Twyford said he "was not going to get into crystal-ball gazing".
"There are lots of different reasons why particular developments, or particular homes, may or may not happen when you hope they will."
Examples of this include consenting issues and the weather.
He said when he had said the Government would have 300 KiwiBuild homes built by July 1, based on the information he had at that stage he thought that was likely.
The Government will reveal its KiwiBuild "recalibration" after the Budget.
However, it would not include any new money to set the policy straight.
Twyford said there would be nothing in the Budget for KiwiBuild.
"We never expected that, or planned for that. The KiwiBuild reset is underway and we will be making announcements sometime in June."