Although Reform wasn't part of coalition negotiations over the last few weeks, the party's popularity has since increased every week, the poll showed.

While Reform is in the lead with its 33.4%, the Centre Party, though still in second place, now is at 20.8% support. The Conservative People's Party of Estonia (EKRE) follows in third place with 16.5% support.

Isamaa has the support of 10%, the Social Democratic Party (SDE) that of 9.1% of voters, Norstat said.

Though it failed to cross the 5% threshold on 3 March, newcomer Estonia 200 is back above the fold at 6%.

Norstat carried out four rounds of polling between 11 March and 8 April and interviewed a total of 4,023 Estonian citizens of voting age.

The polling started at the time it became clear that Centre, EKRE and Isamaa would try to negotiate a coalition and ended when the agreement was signed earlier this week, the Institute for Societal Studies said, though it cautioned that the actual effect of the agreement between the three parties isn't expressed in this poll.