Labor plans for changes to capital gains tax and negative gearing to take effect by 1 January if it is elected at the May election.

On Friday the shadow treasurer, Chris Bowen, announced Labor will take just seven months to consult on and pass its signature housing tax policies and added a new measure to improve tax concessions for build-to-rent schemes.

The timeframe maximises the revenue that Labor can expect from the measures but seemingly closes off the option of delaying the start date in order to soften its impact on a falling housing market.

If Labor is elected, the capital gains tax discount for investments entered into after 1 January 2020 would be halved and from that date only new investment properties will qualify for negative gearing, which allows rental losses to be deducted from other income. The measures are estimated to raise $2.9bn over four years or $35.1bn over 10.

Bowen told ABC Radio that 1 January 2020 was a “sensible start date” and Labor had listened to concerns they could try to rush the measures in by 1 July this year.

The timeframe would allow for a “proper legislative process”, he said, warning crossbench parties to respect Labor’s mandate because by that stage Labor will have taken the housing tax policy to two elections.

Bowen suggested that bringing the policy in “at a quieter time in the property market over the Christmas period” would soften its impact.

Labor first proposed cutting the housing tax concessions in February 2016. The proposals were rejected by the Turnbull government and became one of the major points of difference between the major parties at the 2016 election.

Labor has stuck with the policies, which underpin its projected increases in social spending in areas like health and education, despite falling house prices in Sydney and Melbourne spreading to other capitals due to more restrictive lending practices.

The Coalition argues the policies will increase rents and decrease the value of homes, which lose the negative gearing tax concession when sold into the secondary market.

The assistant treasury minister, Zed Seselja, told ABC Radio that Labor was “delusional” to think introducing the measure over Christmas would soften the blow.

“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,” he said.

The Property Council of Australia said it was “relieved” Labor would not be trying to introduce the measures by 1 July if it wins government because to do so “would have required retrospective legislation, rushed drafting and no opportunity to take expert advice from Treasury and stakeholders”.

“The Property Council remains strongly opposed to this policy and deeply concerned with its potential impacts on housing markets and the broader economy at this uncertain time in the cycle,” it said.

On Friday Labor also announced a new policy to increase tax concessions for build-to-rent schemes to encourage institutional investors into the housing market.

Bowen said Labor will cut the managed investment trust withholding rate in half from 30% to 15% on tax distributions attributable to investments in build-to-rent housing.

He said this will “encourage more construction and stimulate the housing market”.

The Property Council’s chief executive, Ken Morrison, welcomed the measure, describing build-to-rent housing as “an internationally proven way to provide better housing choices for people who rent their home”.

Morrison said the measure would help attract investment and “enable industry to partner with government in providing more affordable housing choices”.