Netflix shares have fallen as spending at the leading streaming television service weighed on quarterly revenue that fell slightly short of expectations.

Netflix shares sank 2% to $345.84 in after-market trades that followed release of earnings figures that showed the Silicon Valley company logged profit of $134m on revenue of $4.2bn in the final three months of last year.

That compared with a profit of $186m on revenue of $3.3 billion in the same period the year previous.

Netflix ended the year with 139 million paying members worldwide, up 29 million from the start of the year.

Operating margin - the money a company keeps after expenses - shrank to 5.2% from 7.5% in a year-over-year comparison of quarters.

The company said it had expected its margin to dip because of the number of shows that launched in the quarter.

"Our multiyear plan is to keep significantly growing our content while increasing our revenue faster to expand our operating margins," Netflix said in a letter to shareholders released along with the earnings report.

Over the past quarter, Netflix said it added 8.8 million new subscribers at the end of last year, with 7.3 million of those outside the US.

On Tuesday Netflix unveiled plans to boost prices for US subscribers as it faces increasing competition in the streaming television market.

The California-based company will raise the price of its most popular streaming plan with high-definition video by 18% to $12.99 a month.