* Q1 likely weaker than Q4 - analysts

* 2024 full year profit likely to improve y-y - analysts

* 2024 capex about 2 trln won, down from 3.6 trln won in 2023

SEOUL, Jan 24 (Reuters) - South Korean flatscreen maker LG Display flagged economic instability this year as it posted on Wednesday its first profit in seven quarters on more shipments of smartphone screens and TV panels during the year-end holiday season.

"Although market volatility will continue this year due to prolonged unstable macroeconomic conditions, we will... (be) strengthening the competitiveness of our organic light-emitting diode (OLED) businesses," said Chief Financial Officer Sung-hyun Kim.

The Apple supplier posted an operating profit of 132 billion won ($98.67 million) for the October-December quarter, versus a loss of 876 billion won a year earlier.

The result matched LG Display's estimate of 132 billion won released earlier this month.

Shipments of OLED displays for smartphones have increased in the fourth quarter, and demand for large and medium-sized screens for products such as TVs and notebooks have increased during the holiday season, the company said.

In the current quarter, analysts expected earnings to weaken due to low seasonal demand, but full-year earnings were seen improving from last year's 2.5 trillion won operating loss on overall demand improvement for electronics products.

LG Display supplies screens for Apple's new headset Vision Pro which starts sales next month, and analysts expect it to boost supply of liquid crystal display (LCD) panels for Samsung Electronics' TVs this year.

Shipments of both small and large OLED panels are also expected to improve, as stocks have been used up and demand improves, they said.

LG Display said it will cut 2024 investment to around 2 trillion won versus 3.6 trillion won in 2023 to strengthen "financial soundness," focusing on essential investments and projects agreed with customers.

Shares in LG Display closed down 2.2% compared to a 0.4% drop in the wider market.

Fourth-quarter revenue rose 1% from a year earlier, to 7.4 trillion won.

($1 = 1,337.7400 won) (Reporting by Joyce Lee and Heekyong Yang; Editing by Aurora Ellis and Miral Fahmy)