The streamer spent a whopping $US12.04 billion ($A16.80 billion) in cash on content last year, up 35 per cent from $US8.9 billion in 2017, according to its fourth-quarter 2018 earnings report.

For the year ahead, Wall Street analysts see that climbing 25 per cent to around $US15 billion on a gross cash basis.

Netflix will continue to burn cash, telling investors on Thursday it expects to record negative $US3 billion in free cash flow in 2019 (similar to last year) and intends continuing to turn to debt markets to fund the spending rate.

The company had $US10.4 billion in long-term debt at the end of 2018, versus $US6.5 billion year earlier.

After paying $15 billion for a "sustained ramp in its original content slate in '19", Netflix's cash content spend growth will "moderate" in the years ahead, BMO Capital Markets analyst Daniel Salmon said in a research note.

He anticipates Netflix's content spending will hit $US17.8 billion in 2020.

Meanwhile, as Netflix continues to write huge cheques for programming, it also has massively increased marketing spending largely to promote those originals.

Marketing costs grew 65 per cent in 2018, to $US2.37 billion. Analysts see that growing - albeit less dramatically - by 22 per cent in 2019, to nearly $US2.9 billion.

One reason Netflix is continuing to make big investments now is that it's going to face serious new streaming competition from media giants Disney, WarnerMedia and NBCUniversal starting later this year.

So it's focusing on building out a wider moat instead of delivering profits, a strategy Wall Street continues to praise.

Australian Associated Press