A Romanian court on Tuesday heard an appeal by controversial influencer Andrew Tate against his 30-day detention for alleged human trafficking, rape and forming a criminal group.

Dressed in black and handcuffed, former professional kickboxer Tate, who is a British-US national, arrived early on Tuesday at the court with his brother Tristan for their hearing behind closed doors.

"It was a long day. The defendants were able to express themselves," their lawyer Eugen Vidineac said at the end of the court hearing, which lasted several hours.

The decision is expected at the earliest "in the evening," he said, adding that he was "confident."

The Tate brothers and two Romanian women were initially detained for 24 hours following their arrest on December 29.

But a Bucharest court granted the prosecutors' request to extend their detention to 30 days because there was a possibility they might try to escape or otherwise evade investigation.

The four suspects are under investigation for allegedly coercing women into "forced labor... and pornographic acts," which they intended to publish online for "substantial financial benefits."

Tate, 36, and his brother, 34, deny the charges, according to Vidineac.

"There is not a single piece of evidence to suggest that a crime of rape has been committed," Vidineac told local media this week.

Prosecutors from Romania's anti-organised crime and terrorism directorate (DIICOT) have been investigating the suspects for several months and searched Tate's villa in April.

Romanian police raided five locations across the country in late December.

So far six potential victims have been identified.

Many of the men's assets, including their collection of luxury cars, were seized.

In 2016, Tate appeared on the Big Brother reality television show. But he was removed after a video emerged showing him attacking a woman.

He then turned to social media platforms to promote his divisive views, before being banned for misogynistic remarks and hate speech.

Tate was allowed back on Twitter after Elon Musk bought the company, and his handle "Cobratate" currently has 4.5 million followers.

Tate and his brother moved to Romania several years ago.