In a move that could significantly affect the greening of campaign '80, the Federal Election Commission has decided to seek a court ruling on the constitutionality of the independent committees that plan to spend millions of dollars to help Ronald Reagan capture the presidency.

The FEC action was promptly hailed by President Carter's campaign officials. Campaign counsel Tim Smith called the decision "a very significant and positive step from our standpoint."

The FEC decision came to a 4-to-2 vote in a closed meeting Wednesday, according to FEC officials. Two Republicans, Max Friedersdorf and Joan Aikkens, cast the negative votes.

The commission's third Republican, Frank Reiche, voted in favor of the action, joining three Democrats, Robert Tiernan, Thomas E. Harris and John McGarry.

The commission decided to file suit in U.S. District Court contending that the so-called independent political spending committees are in fact covered under a section of the Internal Revenue Code. This section prohibits committees from spending more than $1,000 in behalf of a candidate who has been declared eligible to receive public funds for a campaign.

Common Cause has already filed suit in District Court to apply the Internal Revenue Code provision to one of the Reagan committees, Americans for Change, which is headed by Sen. Harrison Schmitt (R-N.M.). This committee has announced plans to spend upward of $20 million.

The FEC voted to intervene in the Common Cause action by asking the court to dismiss that suit and then filing a suit of its own. FEC officials said the commission's suit would differ from that of Common Cause, seeking not enforcement action but a "declaratory judgment." Carter campaign officials said the FEC informed them in a letter that the commission will seek to have the court decide whether the Internal Revenue Code provision applies to the independent committees, and whether such application is constitutional.

In 1976, the Supreme Court declared unconstitutional an independent-expenditure restriction in the Federal Election Campaign Act, on grounds that it violated the right of free speech. But that court ruling on the federal campaign act did not directly apply to the Internal Revenue Code.

The Carter-Mondale campaign and the Democratic National Committee had filed a complaint with the FEC contending that the Reagan campaign should not be eligible for public financing if it is the beneficiary of expenditures from the several independent committees that are being created by prominent Republicans.

Presidential candidates can receive approximately $29 million in federal funds, but cannot also receive private contributions.

The law permits unlimited independent expenditures by individuals or committees as long as there is no contact or coordination between them and the candidate's campaign officials. The Democrats contend that since the independent committees are organized by prominent Republicans, they cannot be considered as truly independent of the Reagan campaign.