A federal Labor government would limit negative gearing concessions to new properties from January 1 next year, earlier than many analysts and commentators predicted.

Key points: Federal Labor argues negative gearing concessions are too generous

Federal Labor argues negative gearing concessions are too generous The change would stop new investors from deducting rental losses from their income tax

The change would stop new investors from deducting rental losses from their income tax It would raise an estimated $2.9 billion over four years

Shadow Treasurer Chris Bowen said the long-awaited start date would still provide enough time for scrutiny of the legislation and more industry consultation.

He again dismissed calls to delay or phase in the change, which is a key point of difference between Labor and the Coalition before a May election.

"This allows it to come in at a quieter time in the property cycle — obviously Christmas and New Year being a quieter time — a good smooth time for implementation," Mr Bowen said.

"This strikes the right balance."

The change would stop new investors from deducting rental losses from their income tax bill, raising an estimated $2.9 billion over four years.

Chris Bowen said the start date would provide time for scrutiny of the legislation. (AAP: Lukas Coch)

Federal Labor has argued this concession is too generous and is unfair because it makes it harder for younger Australians and first-home buyers to enter the market.

Ending the tax concession on January 1, rather than July 1 as many expected, would mean a Labor government begins to collect a share of that $2.9 billion earlier in its first term.

Mr Bowen also argued that delaying the change until property prices recovered from a recent downturn in capital cities would only increase market uncertainty.

"At the last election we said it would come into force 12 months after the election, this time we are saying seven months and they are roughly comparable timeframes," Mr Bowen said.

"This enables proper legislative processes, draft legislation, proper consultation about how the legislation should be framed."

Labor eyes crossbench amid Coalition criticism

The Assistant Minister for Treasury and Finance, Zed Seselja, warned the January start date would hurt both home owners and renters.

"I think it means the pain in the property sector and for millions of Australians would start earlier than expected if Labor comes into office now," Senator Seselja said.

"Just last week we had SQM Research talking about massive rental increases right across Australia if Labor's policy is enacted."

He also dismissed Mr Bowen's suggestion that implementing the change over the Christmas holidays would help make the transition smoother.

"I think that's delusional," he said.

"The problems with this aren't going to be a short-term, temporary problem over a summer break.

"These are problems that will last for a number of years."

If Labor wins the election, it may still need to negotiate with a Senate crossbench that will still include Pauline Hanson and Cory Bernardi.

"I do have some confidence, of course anyone who predicts the result of the Senate is a very brave person," Mr Bowen said.

"I will be making the case directly and personally to the senate that we have taken this to not only one, but two elections.

"We have been upfront about these discussions."

Sorry, this video has expired Aussie Home Loans founder John Symond says negative gearing should be treated "very carefully".

Labor to boost tax concessions for institutional investors

The Federal Opposition has also announced it will reduce taxes for institutional investors that build rental properties.

Labor would cut the managed investment trust withholding rate in half, on tax distributions attributable to investments in build-to-rent housing.

"This means that eligible build-to-rent investments will pay a 15 per cent tax rate, not the 30 per cent rate proposed by Scott Morrison, which would be double the rate paid for investments in shopping centres and office buildings," Mr Bowen will tell a Sydney audience today.

"It will make a build-to-rent [project] viable in Australia and provide a tax rate in keeping with the treatment in other countries."

Editor's note (1/4/19): This story has been updated to clarify Labor's policy is to cease negative gearing on existing properties, not on new investors.