According to an SKDS poll ordered by LTV, a total 23% voters would give their vote for Harmony in the parliamentary election, up from 21.2% in March.
A further 14.6% would vote for the Greens and Farmers Union (up from 13.1%).
6.4% would cast their vote for the National Alliance (down from 7.9%) and a further 5.1% would vote for the Regional Alliance (up from 3.9%).
A total 12.4% say they wouldn't vote in the next parliamentary election while 24.1% don't know whether they'd vote.
The changes in ratings might be connected to the upcoming municipal elections with parties that have put forth candidates for Riga mayor seeing increased ratings.
"I think that it has affected the ratings of one party or another. The rating growth of the Regional Alliance might be related [to the municipal election] ... the party's leader is very visible," SKDS head Arnis Kaktiņš told LTV, referring to Mārtiņš Bondars, the head of the Regional Alliance.
He said it's surprising that Harmony have managed to grow their support as their share of votes is large as it is, and they have a stable voter base.