Twitter has filed a lawsuit against Elon Musk to compel him to complete the social media company's $US44 billion ($64 billion) acquisition.

According to a court filing, the company sought a Delaware court on Tuesday to order the world's richest person to finalize the merger at the agreed $US54.20 per Twitter share.

"Musk apparently believes that he — unlike every other party subject to Delaware contract law — is free to change his mind, trash the company, disrupt its operations, destroy stockholder value, and walk away," the lawsuit states.

The lawsuit initiates what promises to be one of the most significant legal confrontations in Wall Street's history, involving one of the most colorful entrepreneurs in the business world in a case that will hinge on formal contract terms.

Mr. Musk announced on Friday that he was terminating the contract because Twitter had broken the terms of the agreement by failing to respond to requests for information about fraudulent or spam accounts on the platforms, which is essential to its commercial performance.

Mr. Musk did not respond to a request for comment immediately.

The complaint accused Mr. Musk of "a long list" of merger agreement violations that "have cast a pall over Twitter and its business."

Tuesday, shares of the social media site fell to $34.06 from above $50 when Twitter's board approved the deal in late April.

Mr. Musk stated that he was canceling the merger due to a lack of information on spam accounts and incorrect claims, which he deemed a "material adverse event."

He also stated that Twitter's executive departures constituted a failure to conduct business in the regular course.

According to Twitter, it negotiated to remove from the merger agreement language that would have deemed such terminations a violation of normal business requirements.

The social media behemoth referred to Musk's stated reasons as "pretext" that lacked merit, saying that his decision to leave was influenced mainly by a drop in the stock market, particularly for tech equities.

Bret Taylor, chairman of Twitter, stated that the action was brought to hold Mr. Musk "accountable to his contractual obligations."

Musk's primary source of wealth, Tesla shares, has lost 30% of its value since the agreement was disclosed and closed Tuesday at $US699.21.

According to legal experts, based on the publicly available evidence, Twitter appears to have the upper hand due to how Mr. Musk negotiated the purchase, refusing to conduct standard pre-merger due diligence.